NY Legalizes Medical Marijuana: How Vaping Pot Is Different from Smoking

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New York state is set to legalize medical marijuana today, with
Gov. Andrew Cuomo expected to sign a bill passed by the state's
legislature last week. But the proposed law is unique, and
smoking a joint even for medical reasons will remain illegal.

Under the law, doctors can prescribe marijuana compounds for
people who have just a handful of life-threatening and serious
conditions, such as cancer and epilepsy. The new law also bars
smoking the marijuana
flower, and instead limits people to either taking pills,
consuming the plant's oils or extracts, or "vaporizing" the drug.

Experts say that vaporizing cannabis is probably healthier and
less irritating to the lungs than smoking it, but this misty
consumption method may also be more potent than smoking. And
researchers know far less about the long-term effects of "vaping"
the compounds in marijuana extracts or oils, compared with the
effects of inhaling compounds directly from the plant, experts
say. [ Vaping:
How E-cigs Work ]

"We don't have the same safety data for extracts as we do for the
flower," the part of the plant most often burned when smoking
marijuana, said Mitch Earleywine, a psychologist at the
University at Albany in New York, who studies marijuana use.

"Aside from all the carcinogens in it, you're going to get soot
in your lungs" from smoking marijuana, said Dr. John Malouff, a
researcher at the University of New England in Australia, who has
conducted research on the perceived benefits of vaporizing
marijuana. "Because it's not filtered in any way," he said of
smoking, "it's really harsh to everything it touches."

Vaporizers come in many forms, from the bulky plug-in tubes to
the slim, battery-operated
e-cigarette pens. Some heat marijuana flowers until a
fine-mist vapor forms that contains cannabinoids, the compounds
thought to be responsible for marijuana's calming and
mind-altering effects. Most vape pens, however are used to heat
the oils and extracts of marijuana, which are colloquially called
"dabs."

Healthier lungs?

The law's restriction of marijuana consumption to vaping is
sensible from a health perspective, Malouff said.

"If you're going to approve marijuana for medical use, why would
you have people smoke? There's no medicine that people smoke,"
Malouff said.

Several studies suggest that vaporizing is better for health than
smoked marijuana.

Malouff has found that chronic marijuana users cite reduced lung
irritation, as well as improved taste and the absence of a
lingering marijuana smell on their clothes and bodies, as key
reasons for vaping rather than smoking the plant.

A 2004 study in the Journal of Cannabis Therapeutics found that
vaporized marijuana contained little other than cannabinoids, and
a 2007 study found users inhaled fewer toxic compounds and carbon
monoxide when vaping compared with smoking marijuana.

And in 2010, Earleywine and his colleague Nicholas Van Dam found
that marijuana users who complain of respiratory irritation
reported a stark improvement in their symptoms just a month after
switching to vaporized forms of marijuana. Those symptoms include
asthma, shortness of breath and coughing up phlegm. The
researchers also measured objective improvement in the
participants' lung function.

More unknowns

But although vaporizing may sidestep respiratory problems, its
physiological effects could be slightly different than those of
smoked marijuana. That's especially true for vaporized extracts,
which contain little other than cannabinoids such as THC, the
main psychoactive compound in marijuana.

In Malouff's study, many users reported that vaporized marijuana
felt more potent.

By not allowing the smoking of marijuana, lawmakers may have
aimed to avoid undercutting the state's anti-smoking campaigns or
to allow police to distinguish legal medical
marijuana consumers from illegal pot growers, Earleywine
said. But the law could have unintended consequences, as much
less is known about the physiology of vaporizing dabs, he said.

In a forthcoming study in the journal Addictive Behaviors,
Earleywine and his University at Albany colleague Mallory Loflin
have found that compared to marijuana smokers, dab users may more
rapidly develop tolerance to the active compounds, and may also
have a greater risk of
marijuana withdrawal.